The guitar legend took his own life at the age of 64, coroner confirms.

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Ronnie Montrose killed himself with an unregistered .38-caliber revolver, the San Mateo County coroner said Friday, one month after the guitar legend was found dead at his residence in Brisbane, Calif.

The San Francisco Chronicle reported Montrose’s autopsy showed that his blood alcohol level was 0.31 percent at the time of death – almost four times higher than California’s legal limit.

The musician had been struggling with prostate cancer since 2007 and his family at first led fans to believe he had died of cancer, according to the Chronicle.

“By now, the devastating truth of Ronnie’s death is public knowledge," Montrose’s family wrote on his official website. " We hope you can understand why we wanted to keep this news a private family matter for as long as possible.”

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The rocker’s wife, Leighsa Montrose, told Guitar Player that her husband had suffered from clinical depression since childhood and “the expectations he put upon himself were tremendous.”

“Now I see that perhaps he didn’t want to carry these burdens for very much longer,” she said.

In an interview with the Chronicle, she said that her husband “didn’t give any indication” that he planed to kill himself or leave a suicide note.

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“When his mind is made up you can’t reason with him with logic,” she told the paper. “I guess he just let it get the better of him. He was tormented.”

Montrose had played with Van Morrison, Herbie Hancock and Boz Scaggs. He formed his eponymous band in the 1970s with Sammy Hagar.

A tribute concert that reunites Montrose is scheduled at the Regency Ballroom in San Francisco on April 27, according to Guitar World.